A Change Of Heart
by LAminatronic
Summary: Imagine a true pacifist ending. Perfect right? Everyone is happy. Well, the world isn't all black and white. A forgoten foe will come back. A new hero will be born. The real question is. Will the universe hold? Fem!Frisk, Fem!Chara, Frisk X Sans. I own nothing but my OCs and AU idea.
1. Prologue

p style="font-family: Times; font-size: medium;"Hi! Im sorry if this story isn't the best, ( first time writing ) , But I would love to get feedback from you guys on how to improve! -/p  
p style="font-family: Times; font-size: medium;"I don't own undertale. Undertale belongs to Toby Fox ( duh )/p  
p style="font-family: Times; font-size: medium;"The begining of the story is set 20 years after a true pacifist run/p  
p style="font-family: Times; font-size: medium;"Frisk X Sans ( don't worry not much fluff )/p  
p style="font-family: Times; font-size: medium;"emFlashback / Prologue = italics/em/p  
p style="font-family: Times; font-size: medium;"strongspan style="text-decoration-line: underline;"CHARA TALKS LIKE THIS/span/strong/p  
p style="font-family: Times; font-size: medium;"strongBold is Serif thinking to herself/strong/p  
p style="font-family: Times; font-size: medium;"Anyways, Let's start the story./p  
hr style="color: #000000; font-family: Times; font-size: medium;" noshade="noshade" size="1" /  
p style="font-family: Times; font-size: medium;"It started like any normal day,/p  
p style="font-family: Times; font-size: medium;"em*Zzzzzzz*/em/p  
p style="font-family: Times; font-size: medium;"But, it wasn't./p  
p style="font-family: Times; font-size: medium;"em"Serif! Wake up!"/em/p  
p style="font-family: Times; font-size: medium;"em"Huh?" I woke up to see my mom, her short brown hair was very messy, which is very unlikely for her. "Whats going on mom?" I asked. Suddenly, I heard a large blast from downstairs. "Believe me, I have no idea, but your dad might. Come on, we need to go right now!" My mom said as she was pulling on my beige and gold star jacket. "Umm.. Ok, i'll follow you!" As we ran out of my room, I heard another blast, this time it seemed to come from outside./em/p  
p style="font-family: Times; font-size: medium; text-align: center;"emWhen we ran outside, we found dad trying to use a gaster blaster to destroy something, but it stayed perfectly still like nothing happened. In fact, it continued after him. /ememstrongWhatever that thing is, it must be powerful to stay still like that /strong/ememI thought. After one more attempt, dad joined us. "it's no use it just keeps moving foward." he said. I noticed he wasn't wearing his normal fluffy blue jacket, but a white sweater. "First off, WHAT IS THAT THING!" I said as we went to dad's lab, "well, if im right, its a time wave." He looked at us, and juging by the expresstion I was making, he knew i was confused. But mom aperently had a good idea. "Is it related to timelines?" she asked, "yup". "usually this happens when something happened to the current timeline, But I don't know how this is happening without a reset" dad told mom. Me, feeling so clueless about whats happening right now decide to just follow. When we entered the lab, my mom holds the door and dad starts to do somthing on his computer. As soon as dad was done, the door burst open./em/p  
p style="font-family: Times; font-size: medium;"emWhen I looked, I saw all the monsters from the neighbor hood, but they looked... different. They were all wearing red and black clothes, with angry faces. It almost looked like they wanted to hurt us. The black thing that dad was attacking earlier was bigger and almost reached for me. "watch out!" dad said as he pushed me out of the way just in time. I snapped back to reality. "Woah thanks" I said but no response. He and mom were both looking at something. I turned around to see... a black version of mom. This identical twin wore a green sweter with one yellow stripe across, two very red eyes and one very scary smile. "/ememstrongspan style="text-decoration-line: underline;"MISS ME FRISK?/span/strong/emem" She said in a very dark tone. "Chara, WHAT DID YOU DO!" "/ememstrongspan style="text-decoration-line: underline;"Oh, nothing special, I just went back in time to when you first fell and took over the underground. No biggy :)/span/strong/emem" "YOU DID WHAT?!" welp i guess dad started to join in now. /ememstrong"span style="text-decoration-line: underline;"You heard me the first time."/span/strong/ememstrongspan style="text-decoration-line: underline;"Its simple really, but I'll put this in a way you idiots can understand. YOUR NOT THE ONE IN CONTROL ANYMORE/span!"/strong/em/p  
p style="font-family: Times; font-size: medium;"emSuddenly, we heard a scream. "NO!" dad and I yelled. The black time wave covered mom. and when it left, mom was nowhere to be found. All that was left of her was a bright red soul. Next it went after dad. No matter how much he dogged, it eventualy got him. As the black thing got dad he told me somthing. "...go...machine..press..red..." At this point I was expecting my dad to become dust, but he didn't. When the black left he was wearing black and red. He turned around and opened his eyes. His right eye was gone, but his left eye was red."Dad?" I asked. After a few moments he started attacking me. Along with all the other monsters. I chose to make a run for the machine because mercy seemed of the table./em/p  
p style="font-family: Times; font-size: medium;"emI ran in and pressed the red button. "/ememstrongspan style="text-decoration-line: underline;"NOOOOOOOOOOO"/span/strong/emem Chara yelled clearly mad. Slowly, the outside world turned white, and then, the machine also disapered./em/p  
hr style="color: #000000; font-family: Times; font-size: medium;" noshade="noshade" size="1" /  
p style="font-family: Times; font-size: medium;"Heya! So this is the prologue of my story and if you guys like it, ill make more :)/p  
p style="font-family: Times; font-size: medium;"I hope I did a good job. I've been planning this for a while so im happy this is out there now./p  
p style="font-family: Times; font-size: medium;"Plus, if you didn't find out already and im a bad writer, Frisk and Sans had a kid. In my Fanfic sans is 16 when frisk first falls and Frisk is 15 when she falls./p  
p style="font-family: Times; font-size: medium;"Thats all./p  
p style="font-family: Times; font-size: medium;"Baiiiiiiiiiiiiiiiiiii/p  
p style="font-family: Times; font-size: medium;"P.S. : Serif has a combined skeleton monster soul and a human soul so she can switch beween them whenever she likes. Most of the time shes a human when shes calm and a skeleton when shes mad ( cue her eyes glowing gold ) ./p 


	2. Timeline Mix-Up

Hi again!

"Wait are you stalking me?" -Serif

Serif? How did you do that!?

"I have my ways ^-^"

Okay then...

Anyway, I don't own undertale. Undertale belongs to Toby Fox (again, I'm obviously not Toby)

Frisk X Sans (don't worry not much fluff)

 _Flashback / Prologue = italics_

 **CHARA TALKS LIKE THIS**

 **Bold is Serif Narrating**

Underline is now when Serif thinks to herself

Bring on the next chapter!

* * *

 **A few minutes after the outside disappeared, the machine disappeared too. I was falling.**

"Ahhhhhhhhhhhhhhh!"

*thud*

"Oww"

"Huh? What? Why am I covered in snow? What did that machine change the season? How is that going to help me?"

 **Little did I know, I was standing on the answer.**

 **Some time after she got up,**

"I've probably been walking for about an hour now, and where am I? All I can see here is ice and ... snow" A small brown sign caught her attention. "Wait a minute, ice and snow, no sun..." she gasped as she went to the sign, "IM IN THE UNDERGROUND!"

"Omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg omg, so cool!" As you can see, her mom and dad told Serif about the underground when she was little. She never forgot the story. " Ok, ok, calm down serif, you need to come up with a plan." "Maybe there's a small chance some monsters didn't go to the surface. I mean, the underground seems unaffected by chara, maybe I can get some help! In the story, what was that town with the snow called again?" After she looks back at her memories of the story, she giggled. "Now I see why dad lived here, the town's name is a pun!"

 **About an hour later,**

"I finally made it!" Serif cheered as she saw the big Snowdin sign, "YESSSSSSSSSS IT TOOK AN HOUR, BUT IT WAS WORTH IT!" She mentally screamed. "Okay so now I need to be a skeleton since I think monsters will trust a monster more than a human, even if skeletons are rare." With a gold poof, she turned into a skeleton, and came into town. "Whoa, there's a lot more monsters down here then I thought, so mayb-" "SANS!" A loud shoot interrupted her train of thought, "IT'S BEEN EIGHT DAYS AND YOU STILL. HAVEN'T. RECALIBRATED. YOUR. PUZZLES!" Serif decided her plan can wait, she needs to see what that was. With that, she teleported near the source. "Note to self, work on teleportation when this is over." "c'mon give me a break, i've gotten a ton of work today," "SANS NO" "Wait is that dad?" "a skeleTON" Serif was now hiding behind a tree next to where the voices where coming from. She was sure she heard a rim shot after that pun.

*pfft*

As soon as she heard that, Serif's curiosity won. She peeked out of her hiding space, and couldn't believe her eye sockets. She didn't just go to the underground, she went back in time to the seventh fallen child! She saw Frisk hiding behind a conveniently shaped lamp, holding back her laughter, sans making puns, and a very mad papyrus storming off, but not before giving a last "Nyeh" in Sans's direction. "Uuuummmmmmmmmmmmmmmmmmmm wat. This is so weird..." Serif told herself. "After Papyrus left, Frisk finished talking about letting Paps capture her, and Sans teleported away, she came out of her hiding place. "Okay... new plan. Prevent Chara from taking over the past in the first place to save the future. I have to admit, this plan is a little more fool proof then my first one." As she started to walk after Frisk, she didn't see the fragile stick in front of her. Serif accidentally crushed the stick and made a big snap. Frisk turned around, a bit startled by the unexpected sound. In all her resets, she had never seen a skeleton breaking a stick behind her that wasn't Sans. Or a girl skeleton for that matter. Serif on the other hand, was scared she messed up the future. "Uh... Hi I'm Frisk! Who.. are you?"

* * *

Yes, I left the story on a clifhanger. I am evil ZD

"But not as evil as making me sound scared! I wasn't scared!" - Serif

Uh hu, yea right.

Till next chapter,

Baiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii


End file.
